As described in my earlier U.S. Pat. Nos. 4,095,626 and 4,336,830, the pressure in the gasoline being pumped is used to operate a liquid jet gas pump having its liquid inlet in communication with the pressurized gasoline being delivered to individual pumps.
New regulations currently being adopted in California, and in other phase two vapor recovery areas, require a secondary containment of any underground piping containing gasoline even if at atmospheric pressure. While the Healy model 8500 series multi-jet pump has been developed to provide a central vacuum pump for handling a number of vapor recovery nozzles in simultaneous operation, it is basically a multiplication of the type of jet pump shown in the above mentioned patents wherein a plurality of vapor jets exit into a plurality of mixing or diffuser tubes for entraining the vapors.